Carboxylic acid compounds are important industrially as raw materials for drugs, agricultural chemicals or dyes. Of the carboxylic acid compounds, dicarboxylic acid compounds are extremely important as a raw material monomer for production of high-molecular compounds.
Meanwhile, oxidation reaction using nitric acid or a nitrate is an oxidation reaction which is extremely important in organic synthesis. This oxidation reaction using nitric acid or a nitrate is ordinarily used as a process for oxidizing an alicyclic secondary alcohol compound into an aliphatic dicarboxylic acid derivative. In particular, a process of oxidizing cyclohexanol with nitric acid in the presence of ammonium vanadate is known as the most popular oxidation process using nitric acid (Organic Synthesis, Vol. 1, pp. 18-20, 1932).
However, in the above oxidation process using nitric acid, there is a fear that the oxidation reaction proceeds rapidly. Therefore, addition of cyclohexanol to nitric acid containing ammonium vanadate need be conducted very cautiously and the temperature control need be made strictly. Further, since a carbon-to-carbon bond cleavage reaction proceeds in the course of the oxidation reaction, the yield of the adipic acid obtained remains at about 58 to 60%. Thus, this production process is not fully satisfactory.
On the other hand, as a process for oxidizing an alcohol compound into an aldehyde compound or a ketone compound, there is a process which comprises oxidizing an alcohol compound into an aldehyde compound or a ketone compound in an aqueous solution containing 90 volume % (93.1 mass %) of trifluoroacetic acid, using sodium nitrite or sodium nitrate as an oxidizing agent (Thurnal Organischeskoi Khimii, Vol. 24, pp. 488-495, 1988).
This oxidation reaction which is conducted in an aqueous solution containing 90 volume % of trifluoroacetic acid, using a nitrite or a nitrate, is a very mild oxidation reaction which proceeds at room temperature. By this process, an alicyclic secondary alcohol compound can be oxidized into an alicyclic ketone compound almost quantitatively. With this process, however, it is impossible to further oxidize the alicyclic ketone compound obtained, into an aliphatic dicarboxylic acid.